Australian pro golfer David Lutterus is "tremendously lucky" to fill in as caddie for close mate Jason Day at the BMW Championship after a near-fatal motorbike accident six weeks ago.
Day parted ways with caddie Steve Williams last week before summoning childhood mate Lutterus to carry his bag at this week's BMW Championship at Chicago's Medinah Country Club.
Lutterus, who played two seasons on the PGA Tour, was hospitalised for a week in July with severe concussion after crashing a four-wheel motorbike in Ohio.
"He is tremendously lucky," Day told AAP at the BMW Championship.
Day was not with Lutterus during the accident but was horrified to hear that the roll cage on the ATV bike hit Lutterus in the mouth with such force it snapped his jaw bone on one side and shattered it on the other.
"If the roll cage was six inches lower, he may not be walking and six inches higher and he could be (dead)," Day said.
"It's nice for him to be out here walking with me."
The 34-year-old Lutterus said he is glad to be walking, let alone caddying.
But having watched 12-time PGA Tour winner Day freefall out of the top 20 on the world rankings for the first time since 2013, Lutterus believes he can help.
"If the roll cage was six inches lower, he may not be walking and six inches higher and he could be (dead).” – Jason Day
"I've played with him probably more than I've played golf with anyone else," Lutterus told AAP.
"I know his game and I'm excited; I know how great he is and hopefully we can bring that out of him."
Day started 2019 with close mates Luke Reardon and Rika Batibasaga sharing caddie duties before hiring Williams at June's US Open.
World No.22 Day has missed two cuts in his past three starts, at The Open and last week's Northern Trust – the opening event of the PGA Tour's Playoffs series.
Day needs to finish at least solo fifth this week to jump 20 places into the top 30 on the FedExCup standings to advance to the Tour Championship finale.
"I'm outside the bubble looking in and I have to play well this week," Day said.
"There's a little bit of pressure but not that much as I have gone through three different caddies this year.
"I'm trying to relax out there because it's been a long and frustrating year, to be honest."
Day is joined in the 69-man BMW field by fellow Australians Adam Scott and Marc Leishman, who are already qualified for the Tour Championship.
- Evin Priest, Australian Associated Press